Transcript Cardiac Medications - NAU jan.ucc.nau.edu web server

Cardiac Medications
Calcium Channel Blockers,
Nitrates & Beta Blockers
Calcium Channel Blockers
 Verapamil
(Calan, Isoptin)
 Nifedipine (Procardia)
 Diltiazem (Cardizem)
 Amlodipine (Norvasc)
 Bepridil (Vascor)
 Felodipine (Plendil)
 Isradipine
(DynaCirc)
 Mibefradil (Posicor)
 Nicardipine (Cardene)
 Nimodipine (Nimotop)
 Nisoldipine (Sular)
Uses
 Angina
Pectoris
 Hypertension
 Treatment of SVTD’s
Atrial Flutter
 Atrial Fibrillation
 PSVT

Mechanisms of Action
Increase the time that calcium
channels are closed
 Relaxation of arterial smooth
muscle but not a great deal on
venous smooth muscle - significant
afterload effects - little preload
effects

Slows or inhibits the SA and AV
node discharge
 Slows atrioventricular conduction
thus inhibits SVTD’s
 Reduces inotropy in the heart
 Reduced wall tensions and lower
MVO2 demands

Lowers blood pressure due to
arterial smooth muscle relaxation
 Increases AV capture time - prolongs
the refractory period of the AV node
- thus, there is a negative
chronotropic effect
 Reduced vasospasms of epicardial
vessels - reduces Prinzmetal angina

Side Effects
 Bradycardia
 Hypotension,
Syncope
 Angina
 Sedation
 Flushing
Fainting &
Some Concerns…..

Recent evidence in the literature
indicates that nifedipine may have
arrhythmigenic capabilities
Nitrates

Nitroglycerin (Niong, Nitrobid)
Uses Of Nitroglycerin
 Treat
all forms of angina
pectoris usually on an acute
basis rather than a
prophylactic basis
Mechanisms of Action
 Vasodilate
both arterial and
venous smooth muscle
resulting in reduced preload
and afterload
 Reduces end-diastolic filling
pressures
 Increases
blood flow to the
endocardial plexus by dilating
the epicardials
 Lowers MVO2
Side Effects
 Fatigue
& Orthostatic
hypotension
 Syncope
 Headaches
 Nausea
 Vomiting
Beta Blockers
Propranolol (Inderal) non-selective
 Atenolol (Tenorman) beta-1 selective
 Pindolol (Visken) non-selective
 Timolol (Blocarden) non-selective
 Nadolol (Corgard) non-selective

Labetalol (Trandate) non-selective
 Metaprolol (Lopressor) beta-1 selective
 Carvedilol (Coreg) non-selective
 …and many more

 Beta


adrenergic receptors :
beta-1 stimulate heart rate
increases & increases contractile
force
beta-2 stimulate bronchodilation
and vasodilatation
Beta Adrenergic Blockade
Causes…….
 Lowering
of the BP
inhibit norepinephrine release
 inhibit vasoconstriction by
catecholamines

 Reduction
of Cardiac Output
slows electrical conduction velocity
 reduces sympathetic tone over the
heart

 Inhibition
of Renin Release by
the Kidneys
prevents renin from causing
angiotensin I to transform to
angiotensin II which acts as a
potent vasoconstrictor
 thus we have permissive
vasodilatation

 Reduced
MVO2
 Reduction of angina
 After-load is reduced
 Longer diastolic filling times
resulting in increased heart
perfusion
 Inhibits
atrial and ventricular
ectopies
 Beta-blockers are cardioprotective
Medical Uses
 Treatment
of :
angina
 hypertension
 atrial & ventricular dysrhythmias
 panic attacks
 migraine headaches
 reduces the incidence of
esophageal bleeding due to varices

Side Effects
 Bronchoconstriction
- due to
non-selective beta-blockade of
beta-2 receptors
 Inhibition of liver glycogenolysis